<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./js/vue.js"></script>
</head>
<body>
    <div id="app">
        <input type="text" name="mystr" value="mystr" id="mystr" v-model="mystr">
        <button type="button" v-on:click='changeBig'>转大写</button>
    </div>
    <script>
        var app=new Vue({
            el:'#app',
            data:{
                mystr:''
            },
            methods:{
                changeBig:function(){
                    this.mystr=this.mystr.toUpperCase()
                }
            }
        })

    </script>
</body>
</html>